I would have liked to see each contest tag go a little bit longer, since I felt that you had to ask a question towards the beginning of the week to maximize your views. Perhaps Tuesday through next Saturday or something like that.
I think the contest did a good job at attracting new users to the site, as seen by some of the contest questions with high view counts, and it was nice to see a lot of on-topic questions being asked instead of the newest question list always being half full of closed questions. I also enjoyed the fact that mods were a little more relaxed with question closures, and let the community take care of the on-the-fence questions.
As far as what we could do better with in the future, I think we could do a better job at picking tags. The history was probably a bad idea in hindsight since it did promote some off-topic questions, although overall it didn't go as badly as I thought it would and I learned a bit from the questions asked.
I really enjoyed the data-structures and algorithms contests since they gave me some interesting puzzles to think on, but wasn't overly fond of documentation since I hate documentation as it is, so spending time reading about documentation is not my idea of fun :)